Investigation of Cold Forming Cracking Defect of High-Strength Vehicle Structural Steel

摘要

The reason of high-strength vehicle structural steel cracked during cold bending was investigated. The large liquation TiN distributed in grain and the group gathered by multiple liquation TiN can be origin of crack, the mismatching of forming mould leads to large processing stress thereby causing cracking, the metallographic structure showing blurry grain boundaries and cementites gathered there restrains crack propagation hardly, thereby intergranular fracture occurs easily, the fracture morphology characterizes cleavage fracture, macroscopic appearance is brittle fracture.